Naphthalide compounds

ABSTRACT

COLORLESS, BUT COLORABLE NAPHTHALIDE COMPOUNDS ARE DISCLOSED, WHICH ARE REPRESENTED BY THE FORMULA:   3-(4-((R1-)2-N-)PHENYL),3-X-1H,3H-NAPHTHO(1,8-CD)PYRAN-   1-ONE   WHEREIN X IS   1-R-PYRROL-2-YL OR 1,2-DI(R-)INDOL-3-YL   EACH R IS HYDROGEN, AN ALKYL RADICAL HAVING 1 TO 5 CARBON ATOMS, PHENYL OR BENZYL AND EACH R&#39;&#39; IS HYDROGEN OR AN ALKYL RADICAL HAVING 1 TO 5 CARBON ATOMS. THESE COMPOUNDS ARE USED IN PRESSURE-SENSITIVE RECORD MATERIAL AND IN MARK-FORMING MANIFOLD SYSTEMS.

U.S. Cl. 260-32614 R 7 Claims ABSTRACT OF THE DISCLOSURE Colorless, but colorable naphthalide compounds are disclosed, which are represented by the formula:

wherein X is ii f each R is hydrogen, an alkyl radical having 1 to carbon atoms, phenyl or benzyl and each R is hydrogen or an alkyl radical having 1 to 5 carbon atoms. These compounds are used in pressure-sensitive record material and in mark-forming manifold systems.

This invention relates to colorless, but colorable compounds. The compounds can be synthesized from 1,8- naphthoic anhydride. The compounds are used in pressure-sensitive record material and in mark-forming manifold systems.

These compounds are colorless or substantially colorless when in liquid solution, but are converted to darkcolored forms upon reactive contact with an acidic material. In pressure-sensitive mark-forming systems, the unreacted mark-forming components (the colorless, but colorable compound and the acidic material) and a liquid solvent in which each of the mark-forming components is soluble is disposed on or within a sheet support material. The liquid solvent is present in such form that is maintained isolated by a pressure-rupturable barrier from at least one of the mark-forming components until the application of pressure causes a breach of the barrier in the area delineated by the pressure pattern. The application of pressure brings the mark-forming components into reactive contact, thereby producing a distinctive mark.

Colorless, but colorable naphthalide compounds now have been invented.

Accordingly, an object of this invention is to provide colorless, but colorable naphthalide compounds.

Other objects, aspects and advantages of this invention will be apparent to one skilled in the art from the following disclosure and appended claims.

The colorless, but colorable naphthalides of this invention are represented by the formula:

nns? e (United States Patent 0 ice each R is hydrogen, an alkyl radical having 1 to 5 carbon atoms, phenyl or benzyl and each R is hydrogen or an alkyl radical having 1 to 5 carbon atoms. Preferably, each R is hydrogen, methyl, ethyl or phenyl and each R is methyl or ethyl.

Specific examples of these naphthalides are represented by the formula:

wherein X is wherein X is CH3 I CH: N

CH3 I5: (BU U \N I I or l |I These naphthalide compounds are:

The colors developed from these compounds are blues, blue-greens, purples, and the like.

In a preferred embodiment of this invention, the naphthalide and liquid solvent are encapsulated in microscopic capsules which are coated on base sheet record material. In close contact with the base sheet record material is a sensitized undersheet. The base sheet yields the naphthalide under pressure of writing against the sensitized undersheet in a pattern of droplets corresponding to the written matter, in accordance with the disclosure of such a capsule-bearing sheet in U.S. Pat. No. 2,712,507 which issued July 5, 1955, on the application of Barrett K. Green. U.S. Pat. No. 2,712,507 also discloses a preferred method of forming the capsules. Other preferred methods for preparing solvent-containing microscopic capsules are disclosed in U.S. Pat. No. 2,800,457 which issued July 23, 1957, on the application of Barrett K. Green and Lowell Schleicher and in U.S. Pat. No. 3,041,289, which issued on June 26, 1962, on the application of Bernard Katchem and Robert E. Miller.

The encapsulated droplets are released by the rupture of capsules in writing operations. The naphthalide liquid droplets are transferred in the pattern of the data configuration to the top of the underlying sheet is coated or impregnated with at least one material which is an acid reactant with respect to the naphthalide and produces color with any such component that is reactive therewith. Representative acidic coating materials are, on one hand, oil-insoluble minerals or inorganic particulate solid material, represented by kaolin, attapulgite, silica gel, zeolites, and the like, and, on the other hand, organic polymeric acidic materials, such as acid-reacting phenolic resins of oil-soluble characteristics.

The record member consists of a base sheet or web member either of fibrous construction such as paper, or of continuous structure, such as films of organic polymer material, carrying the color reactant in an exposed state with respect to applied liquid. The acid reactant, when of particulate nature, is arranged in intimate juxtaposition to form an apparently unbroken liquid receptive surface, yet substantially each particle individually is available for contact with applied liquid.

Polymeric materials of sufiicient activity in an acid sense and suitable for use in this invention because they are oil-soluble are disclosed in No. 3,672,935, issued June 27, 1972.

Among the oil-soluble organic polymeric materials suitable for use in this invention together with appropriate solvents to be used therewith, acid-reaction phenol-aldehyde and phenol-acetylene polymers, maleic acid-rosin resins partially or wholly hydrolyzed styrene-maleic anhydride copolymers and ethylene-maleic anhydride copolymers, carboxy polymethylene (Carbopol 934), and wholly or partially hydrolyzed vinyl methyl ether-maleic anhydride copolymer are specified as typical of the reactive acidic polymeric materials.

Among the phenol-aldehyde polymers found useful are members of the type commonly referred to as novolaks, which are characterized by solubility in common organic solvents and which are, in the absence of cross-linking agents, permanently fusible. Another group of useful phenol polymeric materials are alkylphenol-acetylene resins, likewise soluble in common organic solvents and possessing permanent fusibility in the absence of being treated by cross-linking material. Generally, the phenolic polymer materials useful in practicing this invention are characterized by the presence of free hydroxyl groups and by the absence of groups, such as methylol, which tend to promote infusibility or cross-linking of the polymer, and by their solubility in organic solvents and relative insolubility in aqueous media.

A laboratory method useful in the selection of suitable phenolic resins is a determination of the infrared radiation absorption pattern of a candidate material. It has been found that phenoic resins showing an absorption in the 3200-3500 cm.- region (which is indicative of the free hydroxyl groups) and not having an absorption in the 1600-1700 cm:- region are suitable. The latter absorption region is indicative of the desensitization of the hydroxyl groups and consequently makes such groups unavailable for reaction with the chromogenic material to be specified.

The liquid solvent portion of this invention is capable of dissolving the mark-forming components. The solvent can be volatile or nonvolatile, and a single or multiple component solvent which is wholly or partly volatile can be used. Examples of volatile solvents useful with the naphthalide and acidic polymer mark-forming components specified are toluene, petroleum distillate, perchloroethylene, and xylene. Examples of nonvolatile solvents are highboiling-point petroleum fractions and chlorinated diphenyls.

Generally, the solvent forming the vehicle to a large extent should be chosen so as to be capable of dissolving at least 1%, on a weight basis, of the naphthalic, preferably in excess of 2%, and a larger amount of polymeric material-up, say or moreto form an efficient reaction. However, in the preferred system, the solvent should be capable of dissolving an excess of the polymeric material, so as to provide every opportunity for maximum coloration at a reaction site.

A further criterion of the selected solvent is that it must not interfere with the mark-forming reaction. In some instances, the presence of the solvent may interfere with the mark-forming reaction or diminish the intensity of the mark, in which case the solvent chosen should be sufficiently vaporizable to assure its leaving the reaction site after having, through solution, brought the mark-forming components into intimate admixture, so that the markforming reaction proceeds.

In the base-acid color system, as stated above, the polymeric mark-forming component(s) chosen must be acidic relative to the naphthalide compound and reactive with the naphthalide material to eflfect the distinctive color formation or color change.

Kaolin is generally known and used in the papermaking industry as China clay and is outstandingly preferable as a particulate oil-insoluble and water-insoluble mineral material of acid characteristisc necessary to color the naphthalides of this invention. A white kaolin is used, and, because of its whiteness, its plate-like particle form, which gives it unparallel coating properties in aqueous slurries, its universal abundance in supply, its historical general usage in the papermaking and paper converting industries, and its low cost, it is an ideal material. Other types of particulate and substantially colorless waterand oil-insoluble minerals of the necessary acid properties are deemed equivalents of kaolin, some being bentonites.

Attapulgite can be used in this invention as an efficient colorless mineral reactant material to color the naphthalide of this invention that react on contact in an electron-donor-acceptor reaction, and, by reason of its high oil absorbency, is doubly useful as an absorbent reactant coating on paper to form color with such compounds dissolved in oil as may be applied to it.

Various methods known to the prior art and disclosed in the aforementioned Pat. No. 3,672,935 and U.S. Pat. No. 3,455,721, issued July 15, 1969, can be employed in coating compositions of the mark-forming materials into their supporting sheets. An example of the compositions which can be coated onto the surface of an underlying sheet of a two-sheet system to react with the capsule coating on the underside of an overlying sheet is as follows:

Coating composition: Percent by weight Phenolic polymer mixture 17 Paper coating kaolin (white 57 Calcium carbonate 12 Styrene butadiene latex 4 Ethylated starch 8 Gum arabic 2 unduly.

EXAMPLE 1 Preparation of 4-diethylaminophenyl 2-carboxylnaphthyl 1 ketone Magnesium shavings, 2.5 g. (1.07 moles) were ground in a flask with a motor driven Teflon stirrer for six hours. To this, was added p-bromo-N,N-diethylaniline, 20.4 g. (0.9 mole) in ml. of dry tetrahydrofuran. This solution was added under nitrogen dropwise with stirring to 1,8-naphthoic anhydride 19.8 g. (0.1 mole) dissolved in r 250 ml. of tetrahydrofuran. The addition took place over a period of one hour. The mixture was filtered, the pH adjusted to 2.6, and extracted with benzene. The benzene extract was washed with water and extracted with 5% sodium bicarbonate solution. The bicarbonate extract was adjusted to a pH of 4 with 6 N hydrochloric acid and 11.6 g. (27%) of the desired keto-acid crystallized M.P. 174-80". Repeated recrystallization of the material afford a M.P. of ZOO-201 C. Anal. Calcd for C I-I NQy C, 75.21; H, 6.31; N, 4.18. Found. C, 75.23; H, 6.18; N, 3.99.

EXAMPLE II Preparation of 3-(4-diethylaminophenyl)-3-(1,2-

dimethylindol-S-yl)-naphthalide A mixture of 1.0 g. (3 mmols) of 4-diethylaminophenyl- 2'-carboxynaphthyl ketone, 1,2-dimethylindole and 10 ml. of acetic anhydride was refluxed ca. one half hour. The reaction mixture was poured into water and extracted with benzene. The benzene was washed with sodium bicarbonate solution and then with water again. Thebenzene was allowed to stand 48 hours. A deposit of 0.25 g. (17.6%) M.P. 227-8 C. was filtered. Evaporation of the benzene afforded 1.45 g. which was redissolved in benzene and diluted with n-heptane. In this way, 0.65 g. (46%) of material M.P. 221-2 C. was obtained. Repeated recrystallization from benzene-heptane gave a sample M.P. 225-7 C. Anal. Calcd for C H N O C, 80.98; H, 6.37; N, 5.90. Found C, 80.81; H, 6.41 N, 5.88. When a solution of this material was applied to a sheet of paper coated with phenolic resin (p-phenylphenol) a blue color was obtained. When applied to a sheet coated with clay, a purple color was obtained.

EXAMPLE IH Preparation of 3-(4-diethylaminophenyl)-3-(2- methylindol-3-yl)-naphthalide According to the procedure described in Example H, a few mgs. of 4-diethylaminophenyl-2'-carboxynaphthyl ketone, 2-methylindole and a few drops of acetic anhydride were heated together for one minute in a test tube. The reaction mixture was cooled, diluted with water, made basic with dilute ammonia, and extracted with benzene. The benzene was washed with water. When this solution was applied to a sheet coated with phenolic resin, a blue color was observed. When applied to a sheet coated with clay, a purple color was observed.

EXAMPLE IV Preparation of 3-(4-diethylaminophenyl)-3-(2- phenylindol-S-yl)-naphthalide The procedure of Example II was repeated with a few mgs. of 4-diethylaminophenyl-2'-carboxy naphthyl ketone, 2-phenylindole and a few drops of acetic anhydride. The work-up was identical to that experiment. When the benzene solution was applied to a sheet coated with resin, a blue color was observed. When applied to a sheet coated with clay, a purple color was observed.

EXAMPLE V Preparation of 3-(4-diethylaminophenyl)-3-(l-methyl pyrrol-2-yl)-naphthalide The work-up of Example 11 was repeated with a few mgs. of 4-diethylaminophenyl-2'-carboxy-naphthyl ketone, l-methylpyrrole and a few drops of acetic anhydride. When the benzene solution was applied to a sheet coated with resin, a blue color was obtained. When applied to a sheet coated with clay, a purple color was observed.

EXAMPLE VI Preparation of 3-(4-diethylaminophenyl)-3-(1- phenylpyrrol-Z-yl) -naphthalide The above work-up of Example II was repeated with a few mgs. of 4-diethylaminophenyl-2'-carboxynaphthyl ketone, l-phenylpyrrole and a few drops of acetic anhydride. When the benzene solution was applied to a sheet coated with resin, a blue color was observed. When applied to a sheet coated with clay, a purple color was observed.

EXAMPLE VII A comparison was made between the 3-(4-diethylaminophenyl) 3 (1,2-dimethy1indol-3-yl) naphthalide prepared in Example II and a most frequently employed color reactant, namely 3,3-bis(4-dimethylaminophenyl)- G-dimethylamino-phthalide. This latter compound is more commonly known as crystal violet lactone or CVL. Prints were made on paper sheets sensitized with 80-20 Resin (80 parts by weight paratertiary-butylphenol and 20 parts by weight para-chlorophenol). Reflectance intensities were obtained on the fresh prints and on the prints after 4 hours'exposure in a daylight fluorescence box. The reflectance values in the following table represent a ratio of the intensity of color to the intensity of the background. A value of 1.000 would indicate a white color. If the reflectance value increases with time, the print fades. Compounds which exhibit good fade resistance will demonstrate smaller increases in R with the passage 1 of time. The obtained reflectance values were:

Fresh 4 hour pn'nt old pn'nt 3-(4-diethylaminophenyl) 3-(1,2-dimethyllndol-3- cglinaphthalide 0.420

It can easily be seen that the naphthalide compound of this invention is more fade resistant than the most frequently employed color reactant, crystal violet lactone.

Although this invention has been described in considerable detail, it must be understood that such detail is for the purposes of illustration only and that many variations and modifications can be made by one skilled in the art without departing from the scope and spirit thereof.

What is claimed is:

1. A compound represented by the formula:

wherein X is and the compound is 3-(4-diethylaminophenyl)-3-(1,2- dimethylindol-3-yl) naphthalide.

4. A compound according to claim 1 wherein R is ethyl, X is and the compound is 3-(4-dicthylaminophenyl)-3-(2- methylindo1-3-yl) naphthalide.

5. A compound according to claim 1 wherein R is ethyl, X is 6. A compound according to claim 1 wherein R is ethyl, X is i CH;

8 and the compound is 3-(4-diethylaminophenyl)-3-(1- methylpyrrol-2-yl) naphthalide.

7. A compound according to claim 1 wherein R is ethyl, X is and the compound is 3-(4-diethylaminophenyl)-3-(1- phenylpyrrol-Z-yl) naphthalide.

References Cited UNITED STATES PATENTS 3,491,112 1/1970 Lin 260315 JOSEPH A. NARCAVAGE, Primary Examiner US. Cl. X.R. 

